There's also the committee factor. Google doesn't hire/no-hire based just on one person's opinion. If half your committee says, "90% of our engineers use his thing!" and the other half says, "But he can't code on a whiteboard!" then the committee is already kinda likely to take a pass due to lack of consensus. If there's any doubts at all on culture fit, which Google absolutely does care a great deal about, even more so. That said, when I was there, I interviewed someone who was essentially going to be my partner on something and everyone else (who weren't going to be working with this person) ranked the person poorly and I was the sole voice of (positive) dissent. I wasn't on the committee, so I don't know what their logic was, but the person was hired. And they were great. So it's not always even a majority opinion thing with the interviewers. In a nutshell, not only are we dealing with incomplete information here, we're dealing with VERY incomplete information.